Abstract: In accordance with the process, a continuously fed viscoplastic material is subjected to a vacuum treatment in a thin layer with subsequent formation of a higher pressure zone from the material. Then the material is again subjected to the vacuum treatment in a thin layer, and a second higher pressure zone is formed from the material prior to feeding it to a next production stage. In an apparatus for carrying out the process for vacuum treatment, there is provided a container accommodating an auger having main and auxiliary turns running in opposite directions for feeding the material in a thin layer and for forming higher pressure zones from the material. There are provided a pipe in the container which is connected to a vacuum system for forming a vacuum zone in the container and means returning the material from one of the higher pressure zones back to the vacuum zone. The production process of vacuum treatment is thereby considerably accelerated and the material of better quality is obtained.